Hi Andy,
I am sorry, this is not supported in the current version, however i see this being useful. I will try to introduce a new property for that. Any suggestions on how this would make sens to round?

For our data, rounding to the nearest whole number would work, but it would be good if it was possible to specify an 'increment' and have the control round the axis labels to that increment, so we could specify 1, 0.5, 0.1 etc.

actually for whole numbers that would be possible using the charts["gridXNumberFormat"] of the group containing the chart:

e.g. set the charts["gridXNumberFormat"] of grp "myChart" to "#"

I will look into the rounding stuff for the next iteration of the library. Currently I am working a lot on the next iteration of animationEngine, so until this is released I will not add features to charts. Of course if there are obvious bugs that get reported those will get fixed with high priority, however, new features won't arrive before AE 3 is out of the door (which should not be too far from now though)